The disclosure of Japanese Patent Applications No. 2010-38225 on Feb. 24, 2010, including its specification, claims and drawings, is incorporated herein by reference in its entirety.
1. Field of the Invention
The present invention relates to a suction conduit (tube) device or particularly to a suction tube communicating with a treatment instrument insertion channel and configurations of a suction tube and a suction valve of an endoscope in which the suction valve that opens/closes the suction tube is arranged.
2. Description of the Related Art
In an endoscope, a suction function (a suction conduit device) for suctioning a saline solution, blood, body tissues, body wastes and the like in the body using a treatment instrument insertion channel, a suction tube, and a suction valve or the like is disposed.
FIG. 5 shows an example (similar to Japanese Patent Laid-Open No. 2007-185276 (Document 1)) of a prior-art suction valve (suction control portion) constituting the suction conduit device, and in this suction valve, a piston shaft 2 is integrally fixed to a suction button 1 made of an elastic body, and this piston shaft 2 is arranged so as to move vertically through an internal passage (valve-portion passage) of a main body 3. On the lower side of this main body 3, a suction tube 4 is connected, and a suction pump is connected to a connection tube 5 formed so as to extend from the main body 3. Also, on a side wall of the suction button 1, an opening 1a for suctioning air is formed.
According to such suction valve, as shown in FIG. 5, by pressing the suction button 1, the piston shaft 2 is moved downward, and a valve portion 6 and an opening 2a of the piston shaft 2 are opened, whereby a suction operation by suctioning by the suction pump is performed, and the saline solution and the like present in the body is suctioned and discharged. Also, by releasing the pressing on the suction button 1, the valve portion 6 is closed, and the air is suctioned through the opening 1a of the suction button 1, and suctioning through the suction tube 4 is not performed.
However, with the prior-art suction conduit device of an endoscope, when solid substances or substances with high viscosity (such as coagulated blood, tissue pieces and the like) are to be suctioned from inside the body, there are problems that a large load is applied and a passage inside the suction valve might be clogged by the suctioned substances.
In the case of the suction valve in FIG. 5, since the passage of the valve portion 6, that is, a passage between the side face of the piston shaft 2 and the side face of the internal passage of the main body 1 is narrowed, this passage or its vicinity is clogged by the suctioned substances. And such clogging by the suctioned substances might incur a failure of the device or interruption of endoscopic observation or the like.
In the prior-art references, there is a conduit switching valve in which a passage is not formed between the side face of the piston and the side face of the internal passage of the main body (cylinder) as shown in Japanese Patent Laid-Open No. 2004-223121 (Document 2).
The present invention was made in view of the above problems and has an object to provide a suction conduit device of an endoscope that reduces a suction load when a solid substance, a substance with high viscosity or the like is suctioned and prevents clogging of the passage in the suction valve by the suctioned substances.